I'm also looking a t the cost, saving some money is always good.
That said, since you are looking at getting the AMD Ryzen 7 2700X 8-Core 3.7 GHz Processor.
You might want to get AMD Wraith Ripper by Cooler Master, Seven Heatpipe, Dual Heatsink, Designed for The Threadripper. $159.99 CAD

Specifically designed for AMD Ryzen Threadripper, the Cooler Master Wraith Ripper is an ultimate choice of air cooler for gamers, overclockers and content creators.
It’s equipped with special air-guide armor, dual tower heatsink, and 7-heatpipe array to ensure maximum cooling efficiency without annoying fan noise or vibration.
The cooler also has addressable RGB LED, allowing you to customize its lighting with AMD RGB software.